The present invention relates to a method of measuring an eyeglass frame, and an eyeglass frame measuring apparatus which are used for grinding an eyeglass lens on the basis of measurement data of an eyeglass frame, and also to an eyeglass lens grinding apparatus.
An apparatus is known which measures the frame configuration of an eyeglass frame and grinds an eyeglass lens on the basis of data of the measurement. In such a process, a method in which the process is performed on the basis of frame configuration data for each of the right and left eyes may be employed. In the case where right and left frame configurations are different from each other, when lenses are processed so as to respectively conform to the configurations, however, the resulting eyeglass may look strange. Therefore, such a process is usually performed by using data in which data for one of the right and left configurations is set as a reference and data for the other configuration is obtained by inverting (mirror-inverting) the reference data.
Usually, the right and left frame configurations of an eyeglass frame are substantially bilaterally symmetrical with each other. However, it is not rare that the positional relationship between the right and left frames are slightly relatively rotated as shown in FIG. 8 due to a problem in production. This easily occurs particularly in an eyeglass frame such as a metal frame which is produced by separately producing right and left frames and then bonding the frames together via a bridge. Furthermore, an eyeglass frame may be deformed during transportation and handling after production. Therefore, in a process using a mirror-inverted data, even when the one lens is processed on the basis of the reference data at a correct axial degree (characteristic), the axial degree of the other lens contains an error, thereby causing a problem in that the axis degree of an eyeglass lens mounted to the frame fails to conform to a predetermined one.